Semiconductors with narrow energy gaps have electronic properties, including a high mobility and strong spin-orbit coupling, that are advantageous for electronic device applications. The switching speed of a field-effect transistor and the sensitivity of a geometrical magnetoresistor are improved by a high carrier mobility. In addition to these traditional devices, we are studying devices that take advantage of quantum-mechanical or spin-orbit effects. We are also exploring the properties of holes in InSb and InxGa1-xAs quantum wells, which are predicted to have stronger spin-orbit effects than electrons and would be required for CMOS logic applications.
